clk: qcom: support for alpha pll properties

Alpha PLL is a generic name used for QCOM PLLs which uses L and
Alpha values for configuring the integer and fractional part.
QCOM SoCs use different types of Alpha PLLs for which basic
software configuration part is common with following differences.

  1. All these PLLs have the same basic registers like
     PLL_MODE, L_VAL, ALPHA_VAL but some of the register offsets are
     different between PLLs types.

  2. The dynamic programming sequence is different in some
     of the Alpha PLLs

  3. Some of the PLLs don’t have 64 bit config control, 64 bit
     user control, VCO configuration, etc.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>